OCR GCSE Combined Science A (Gateway) Biology Paper 1 Foundation June 2024 question paper J250/01

A student prepares a microscope slide to view colourless plant cells.

Which type of substance is used to colour the cells?

A Acid

B Hormone

C Lipid

D Stain

The total magnification of an image viewed using a light microscope is calculated using a formula.

What is the correct formula for total magnification?

A Total magnification = eyepiece lens magnification × objective lens magnification

B Total magnification = eyepiece lens magnification – objective lens magnification

C Total magnification = eyepiece lens magnification + objective lens magnification

D Total magnification = eyepiece lens magnification ÷ objective lens magnification

Plasmids are small rings of genetic material.

Which row describes where plasmids are found?

The graph shows the effect of pH on the activity of two enzymes.

Identify the pH where both enzymes are active.

The model represents a molecule found inside human cells.

Which of these describes this model?

A Monomer and a double helix

B Monomer and a double twist

C Polymer and a double helix

D Polymer and a double twist

The diagrams show stages in the hypothesis used to explain the mechanism of enzyme action.

Which term describes this hypothesis?

A Active site

B Denaturing

C Enzyme specificity

D Lock and key

The graphs show how the rate of water uptake in plants can change.

Which graph shows the correct effect of increased air movement on the rate of water uptake?

The diagram shows drawings of red blood cells.

Complete the sentences about red blood cells. Use words from the list.

biconcave chlorophyll haemoglobin helix

nitrogen oxygen water

Red blood cells are adapted to transport........ around the body.

One adaptation is the red pigment........ found inside the cells.

Another adaptation is their........ shape.

Bone marrow cells inside human bones differentiate to form red blood cells.

What name describes cells that can differentiate?

This diagram shows the human heart.

The table shows some information about the heart.

Use the diagram to complete the table.

Hormones are transported in the blood.

The graph shows the changes that occur to female hormone concentrations in the blood during the menstrual cycle.

Which day of the cycle does hormone X reach its peak?

Draw a line from each hormone to its correct name.

Plants photosynthesise to produce food.

Oxygen is a product of photosynthesis.

What are the two reactants in photosynthesis?

Which statements about photosynthesis are true and which are false ?

Tick (✓) one box in each row.

The diagram shows apparatus used to investigate photosynthesis.

The number of oxygen bubbles released each minute indicate the rate of photosynthesis.

A student counts the number of oxygen bubbles released from the pondweed.

They count 23 bubbles in 3 minutes.

Calculate the rate of photosynthesis.

Give your answer to the nearest whole number.

Rate =........ bubbles per minute

The student develops their investigation to find the effect of light intensity on the rate of photosynthesis.

Describe how they should develop their investigation.

In your answer include:

• any additional apparatus they will need that is not shown in the diagram

• one variable they will need to control

• how they will change light intensity.

A study recorded the reaction time of people of different ages.

The table shows the mean reaction times for the different age groups.

Which age group had the fastest mean reaction time?

Calculate the percentage increase from the 25–34 age group’s mean reaction time and the 65+ age group.

Give your answer to 3 significant figures.

When drivers are at the UK limit for blood alcohol content it increases their reaction time by 0.12 s.

A 25 year old drives at the UK limit.

Which age group has a mean reaction time closest to this 25 year old driver?

Calculate the surface area to volume ratio of agar cube C.

Write your answer in the table.

The student has two results for their agar cube B experiment. The result for their first attempt was 122 seconds.

Suggest why the student repeated the experiment to obtain a second result.

* Tapeworms live in the digestive system of a host animal.

• They feed by absorbing nutrients directly from their animal host.

• The nutrients diffuse across the outer surface of the tapeworm to all the cells in their body.

• The tapeworm has a surface area to volume ratio similar to agar cube A.

Explain why having a surface area to volume ratio similar to agar cube A is an advantage to the tapeworm.

Use data from the table.

The arrows show direction of movement inside the vessels.

Give two reasons why Fig. 15.2 shows phloem vessels.

Compare the type of substances transported in xylem and phloem vessels.

Explain how the transport of substances through xylem changes on a warm day compared with a cold day.

A teacher investigates the effect of different enzymes on starch. They want to find out if the enzyme breaks down the starch into sugar.

This is the method they use:

• Add 1 cm³ of an enzyme to 5 cm³ of starch solution in a boiling tube.

• Leave the mixture for 5 minutes.

• Add Benedict’s solution to the mixture.

• Place the boiling tube in a hot water bath.

• Record the colour of the Benedict’s solution after heating.

Benedict’s solution is a blue solution that, when heated, forms a coloured precipitate if sugar is present.

Fig. 16.1 shows how the teacher tested for the presence of sugar in the mixture.

Fig. 16.1

The teacher repeats the method with different enzymes.

Identify the dependent variable in this investigation.

Suggest one hazard in this investigation and the precaution the teacher should take.

Complete the table.

The concentration of sugar in mixture C stated in the table is not an accurate value.

How can the student tell that it is not an accurate value?

The amount of light absorbed by different colours can be measured.

The graph compares absorbance with the percentage of sugar concentration.

The teacher investigates the light absorbed by the different coloured mixtures.

They record an absorbance of 0.2 for mixture C.

Use the graph to find the sugar concentration of mixture C.

The answer to (i) is outside the range stated in the results table.

Suggest how the student could improve their method to find out how precise their measurement is for mixture C.